Slow Flyer Propeller,9 x 3.8, SF This is the APC Propellers 9x3.8 Slo-Flyer Tractor Airplane Propeller. Features: Computer-optimized design gives these props a thinner profile and more "bite" with less noise.Lightweight molded nylon construction reduces rotating mass for higher output and longer life.Reinforcing carbon fibers help maintain true, constant pitch at any rpm.This propeller produces a lot of torque, even at low speeds. APCs Slo-Flyer pr